Fluid pressure actuated valve operator

Claim 1

An operator mountable on equipment such as a gate valve for reciprocating a reciprocable element thereof such as a gate valve gate, comprising: an annular bonnet member having securement means thereon for fixedly securing the bonnet on the equipment; said bonnet having a bore for reciprocably receiving a portion of the element to be reciprocated; and packing means received in said bore for sealing against the element to be reciprocated; a cylinder member including tubular sidewall means closed at opposite ends by upper and lower annular end wall means defining a housing with said cylinder; means sealing and securing the lower annular end wall coaxially upon the bonnet so the element to be reciprocated may protrude up into within the cylinder; means defining external helical threading circumferentially on said bonnet; an annular bonnet drive gear; means co-axially mounting the bonnet drive gear in the bore of said lower annular end wall means; said annular bonnet drive gear having means defining internal helical threading thereon which is complementary with the external helical threading defined on the bonnet; a bonnet drive pinion mounted on the lower end wall means in meshing engagement with the bonnet drive gear and accessable from exteriorly of said operator, so that the bonnet drive pinion, upon being rotated from exteriorly of the operator, rotates the bonnet drive gear to engage said threading when rotated in one angular sense and to disengage said threading when rotated in the opposite angular sense; an annular piston slidingly coaxially received within the cylinder, means sealing the outer peripheral extent of the piston with respect to the inner periphery of the tubular sidewall means of the cylinder; port means on said cylinder for admitting and releasing pressurized fluid to and from the cylinder above the piston for reciprocating the piston; port means on said cylinder below the piston for admitting and exhausting fluid to and from the cylinder below the piston to permit the piston to reciprocate in response to admission and release of said pressurized fluid above the piston; a compression coil spring coaxially mounted to bear at one end against the housing and to resiliently urge the piston toward adjacency with the upper end wall means; annular sealing means in the bore of said cylinder annular upper end wall means; an upper stem slidingly received in the last-mentioned bore and sealed with respect thereto by the last-mentioned sealing means; said upper stem having downwardly facing shoulder means near the lower end thereof, the upper stem being insertable through the bore of said piston down to said shoulder means; and said upper stem having securement means thereon below said shoulder means for removably securing the lower end of the upper stem to the element to be reciprocated, within the cylinder, with the piston abutting the shoulder means.